The present invention relates to improvements in apparatus for permitting manipulation of containers with exposed but undeveloped films therein in a dark chamber. More particularly, the invention relates to improvements in apparatus which enable the hands of an attendant to gain access to selected containers in the dark chamber.
U.S. Pat. No. 4,253,788 granted Mar. 3, 1981 to Oaks et al. for "Film unloading and handling mechanism" discloses an apparatus which defines a dark chamber for removal of roll film from a spool or cassette and for unwinding of roll film from the core. The apparatus of Oaks et al. further comprises a guide which directs certain defective containers for roll film into a collecting receptacle, and a monitoring device which generates signals in response to detection of defective containers in order to ensure that each defective container is diverted to the guide and enters the collecting receptacle. For example, the monitoring device can ascertain that an exposed film cannot be withdrawn from its container so that the container must be removed for extraction of the confined film in a different way. The collecting receptacle is or resembles a bag, and the containers which accumulate therein cannot be removed except by sealing the room against penetration of light. This is a time-consuming operation because the room must be equipped with means for preventing penetration of radiation which could affect the quality of exposed film frames.
Proposals to avoid the need for conversion of a normally lit room into a dark chamber preparatory to withdrawal of defective containers for exposed but still undeveloped photographic film include the provision of a sealing device which has openings for insertion of hands so that the person in charge can reach the contents of the bag without darkening the room in which the apparatus is installed. The sealing device which is provided with such openings is followed by a second sealing device resembling or constituting a shiftable blind which must be pushed or pulled in a first direction in order to afford access to defective containers and in a second direction counter to the first direction in order to prevent penetration of light into the space for the bag. This is a time consuming procedure and, moreover, the prevention of penetration of light into the space for the bag depends entirely on the conscientiousness of the operator who might forget to return the blind to the sealing position so that light will reach the space for the bag as soon as an operator inserts her or his hands through the openings of the first sealing device. Penetration of light into the space for the bag which contains defective containers can affect the quality of customer films or can entail total damage if the quantity of light is sufficient to render the exposed film in a defective container useless for development and for the making of diapositives or prints therefrom.